Numerous proposals have been made in recent years for so-called passive vehicle occupant restraint belt systems, that is, restraint belt systems designed to transfer automatically between a restraining configuration and a releasing configuration in response to opening and closing of the vehicle door. Many of those proposed systems have a guide rail mounted generally above the vehicle door, on the lower portion of the vehicle door or somewhere along the center of the vehicle inboard of the seat and a slider that carries either a moving anchor or belt guide that moves along the guide rail to transfer the belt between the restraint and release configurations. The slider, in turn, is connected to a drive wire that drives it along the rail. In many cases, the guide rail is curved, sometimes rather sharply.
When the slider and the portion of the drive wire that moves along the guide rail traverse the curved portion of a curved guide rail, the drive wire is subjected to bending. The drive wire, of course, is semi-flexible and reasonably capable of enduring the normal bending stresses. However, in the common way of fastening the drive wire to the slider, namely by a pressed-on fitting, the bending of the drive wire at the point where it is joined to the slider produces a highly concentrated stress. Such concentrated stress, when applied over numerous cycles, can produce failure of the drive wire at the point where it is fastened to the slider.
One possible solution to the problem is to minimize or eliminate bends in guide rails, thus avoiding the stress concentration problem altogether. However, there are various belt passive restraint belt systems in which it is highly advantageous to have a fairly sharp curve in the guide rail. Examples of such systems are described below and illustrated in the accompanying drawings.